ICFO - The Institute of Photonic Sciences
http://hdl.handle.net/2117/23727
2024-03-28T12:20:42ZInSb/InP Core–Shell Colloidal Quantum Dots for Sensitive and Fast Short-Wave Infrared Photodetectors
http://hdl.handle.net/2117/401812
InSb/InP Core–Shell Colloidal Quantum Dots for Sensitive and Fast Short-Wave Infrared Photodetectors
Peng, Lucheng; Wang, Yongjie; Ren, Yurong; Wang, Zhuoran; Cao, Pengfei; Konstantatos, Gerasimos
2024-02-13T15:56:35ZPeng, LuchengWang, YongjieRen, YurongWang, ZhuoranCao, PengfeiKonstantatos, GerasimosControlling Atom-Photon Bound States in an Array of Josephson-Junction Resonators
http://hdl.handle.net/2117/374230
Controlling Atom-Photon Bound States in an Array of Josephson-Junction Resonators
Scigliuzzo, Marco; Calajò, Giuseppe; Ciccarello, Francesco; Perez Lozano, Daniel; Bengtsson, Andreas; Scarlino, Pasquale; Wallraff, Andreas; Chang, Darrick E.; Delsing, Per; Gasparinetti, Simone
Engineering the electromagnetic environment of a quantum emitter gives rise to a plethora of exotic light-matter interactions. In particular, photonic lattices can seed long-lived atom-photon bound states inside photonic band gaps. Here, we report on the concept and implementation of a novel microwave architecture consisting of an array of compact superconducting resonators in which we have embedded two frequency-tunable artificial atoms. We study the atom-field interaction and access previously unexplored coupling regimes, in both the single- and double-excitation subspace. In addition, we demonstrate coherent interactions between two atom-photon bound states, in both resonant and dispersive regimes, that are suitable for the implementation of swap and cz two-qubit gates. The presented architecture holds promise for quantum simulation with tunable-range interactions and photon transport experiments in the nonlinear regime.
2022-10-10T09:42:02ZScigliuzzo, MarcoCalajò, GiuseppeCiccarello, FrancescoPerez Lozano, DanielBengtsson, AndreasScarlino, PasqualeWallraff, AndreasChang, Darrick E.Delsing, PerGasparinetti, SimoneEngineering the electromagnetic environment of a quantum emitter gives rise to a plethora of exotic light-matter interactions. In particular, photonic lattices can seed long-lived atom-photon bound states inside photonic band gaps. Here, we report on the concept and implementation of a novel microwave architecture consisting of an array of compact superconducting resonators in which we have embedded two frequency-tunable artificial atoms. We study the atom-field interaction and access previously unexplored coupling regimes, in both the single- and double-excitation subspace. In addition, we demonstrate coherent interactions between two atom-photon bound states, in both resonant and dispersive regimes, that are suitable for the implementation of swap and cz two-qubit gates. The presented architecture holds promise for quantum simulation with tunable-range interactions and photon transport experiments in the nonlinear regime.Neutron Ionization of Helium near the Neutron-Alpha Particle Collision Resonance
http://hdl.handle.net/2117/368342
Neutron Ionization of Helium near the Neutron-Alpha Particle Collision Resonance
Pindzola, M. S.; Colgan, J.; Ciappina, M. F.
Neutron-impact single and double ionization cross sections of the He atom are calculated near the neutron-alpha particle collision resonance. Calculations using the time-dependent close-coupling method for total and differential cross sections are made at 8 incident neutron energies ranging from 250 to 2000 keV. At the resonance energy peak the double ionization cross sections unexpectedly become larger than the single ionization cross sections. This finding appears to be related to the high velocity of the recoiling alpha particle, which makes it unlikely that the atomic electrons can recombine with the alpha particle nucleus, enhancing the double ionization cross section.
2022-06-13T10:24:25ZPindzola, M. S.Colgan, J.Ciappina, M. F.Neutron-impact single and double ionization cross sections of the He atom are calculated near the neutron-alpha particle collision resonance. Calculations using the time-dependent close-coupling method for total and differential cross sections are made at 8 incident neutron energies ranging from 250 to 2000 keV. At the resonance energy peak the double ionization cross sections unexpectedly become larger than the single ionization cross sections. This finding appears to be related to the high velocity of the recoiling alpha particle, which makes it unlikely that the atomic electrons can recombine with the alpha particle nucleus, enhancing the double ionization cross section.Cation disorder engineering yields AgBiS2 nanocrystals with enhanced optical absorption for efficient ultrathin solar cells
http://hdl.handle.net/2117/365008
Cation disorder engineering yields AgBiS2 nanocrystals with enhanced optical absorption for efficient ultrathin solar cells
Wang, Yongjie; Kavanagh, Seán R.; Burgués-Ceballos, Ignasi; Walsh, Aron; Scanlon, David O.; Konstantatos, Gerasimos
Strong optical absorption by a semiconductor is a highly desirable property for many optoelectronic and photovoltaic applications. The optimal thickness of a semiconductor absorber is primarily determined by its absorption coefficient. To date, this parameter has been considered as a fundamental material property, and efforts to realize thinner photovoltaics have relied on light-trapping structures that add complexity and cost. Here we demonstrate that engineering cation disorder in a ternary chalcogenide semiconductor leads to considerable absorption increase due to enhancement of the optical transition matrix elements. We show that cation-disorder-engineered AgBiS2 colloidal nanocrystals offer an absorption coefficient that is higher than other photovoltaic materials, enabling highly efficient extremely thin absorber photovoltaic devices. We report solution-processed, environmentally friendly, 30-nm-thick solar cells with short-circuit current density of 27 mA cm−2, a power conversion efficiency of 9.17% (8.85% certified) and high stability under ambient conditions.
2022-03-30T10:04:02ZWang, YongjieKavanagh, Seán R.Burgués-Ceballos, IgnasiWalsh, AronScanlon, David O.Konstantatos, GerasimosStrong optical absorption by a semiconductor is a highly desirable property for many optoelectronic and photovoltaic applications. The optimal thickness of a semiconductor absorber is primarily determined by its absorption coefficient. To date, this parameter has been considered as a fundamental material property, and efforts to realize thinner photovoltaics have relied on light-trapping structures that add complexity and cost. Here we demonstrate that engineering cation disorder in a ternary chalcogenide semiconductor leads to considerable absorption increase due to enhancement of the optical transition matrix elements. We show that cation-disorder-engineered AgBiS2 colloidal nanocrystals offer an absorption coefficient that is higher than other photovoltaic materials, enabling highly efficient extremely thin absorber photovoltaic devices. We report solution-processed, environmentally friendly, 30-nm-thick solar cells with short-circuit current density of 27 mA cm−2, a power conversion efficiency of 9.17% (8.85% certified) and high stability under ambient conditions.Human CASPR2 antibodies reversibly alter memory and the CASPR2 protein complex
http://hdl.handle.net/2117/363805
Human CASPR2 antibodies reversibly alter memory and the CASPR2 protein complex
Joubert, Bastien; Petit-Pedrol, Mar; Planagumà, Jesús; Mannara, Francesco; Radosevic, Marija; Marsal, Maria; Maudes, Estibaliz; García-Serra, Anna; Aguilar, Esther; Andrés-Bilbé, Alba; Gasull, Xavier; Loza-Alvarez, Pablo; Sabater, Lidia; Rosenfeld, Myrna R.; Dalmau, Josep
Objective
The encephalitis associated with antibodies against contactin-associated protein-like 2 (CASPR2) is presumably antibody-mediated but the antibody effects and whether they cause behavioral alterations are not well-known. Here, we used a mouse model of patients’ IgG transfer and super-resolution microscopy to demonstrate the antibody pathogenicity.
Methods
IgG from patients with anti-CASPR2 encephalitis or healthy controls were infused into the cerebroventricular system of mice. The levels and colocalization of CASPR2 with transient axonal glycoprotein-1 (TAG1) were determined with Stimulated Emission Depletion (STED) microscopy (40-70μm lateral resolution). Hippocampal clusters of Kv1.1 voltage-gated potassium channels (VGKC) and GluA1-containing AMPA receptors were quantified with confocal microscopy. Behavioral alterations were assessed with standard behavioral paradigms. Cultured neurons were used to determine the levels of intracellular CASPR2 and TAG1 after exposure to patients’ IgG.
Results
Infusion of patients’ IgG, but not control IgG, caused memory impairment along with hippocampal reduction of surface CASPR2 clusters and decreased CASPR2/TAG1 colocalization. In cultured neurons, patients’ IgG led to an increase of intracellular CASPR2 without affecting TAG1, suggesting selective CASPR2 internalization. Additionally, mice infused with patients’ IgG showed decreased levels of Kv1.1 and GluA1 (two CASPR2 regulated proteins). All these alterations and the memory deficit reverted to normal after removing patients’ IgG.
Interpretation
IgG from patients with anti-CASPR2 encephalitis cause reversible memory impairment, inhibit the interaction of CASPR2/TAG1, and decrease the levels of CASPR2 and related proteins (VGKC, AMPAR). These findings fulfill the postulates of antibody-mediated disease and provide a biological basis for antibody-removing treatment approaches.
2022-03-10T10:09:22ZJoubert, BastienPetit-Pedrol, MarPlanagumà, JesúsMannara, FrancescoRadosevic, MarijaMarsal, MariaMaudes, EstibalizGarcía-Serra, AnnaAguilar, EstherAndrés-Bilbé, AlbaGasull, XavierLoza-Alvarez, PabloSabater, LidiaRosenfeld, Myrna R.Dalmau, JosepObjective
The encephalitis associated with antibodies against contactin-associated protein-like 2 (CASPR2) is presumably antibody-mediated but the antibody effects and whether they cause behavioral alterations are not well-known. Here, we used a mouse model of patients’ IgG transfer and super-resolution microscopy to demonstrate the antibody pathogenicity.
Methods
IgG from patients with anti-CASPR2 encephalitis or healthy controls were infused into the cerebroventricular system of mice. The levels and colocalization of CASPR2 with transient axonal glycoprotein-1 (TAG1) were determined with Stimulated Emission Depletion (STED) microscopy (40-70μm lateral resolution). Hippocampal clusters of Kv1.1 voltage-gated potassium channels (VGKC) and GluA1-containing AMPA receptors were quantified with confocal microscopy. Behavioral alterations were assessed with standard behavioral paradigms. Cultured neurons were used to determine the levels of intracellular CASPR2 and TAG1 after exposure to patients’ IgG.
Results
Infusion of patients’ IgG, but not control IgG, caused memory impairment along with hippocampal reduction of surface CASPR2 clusters and decreased CASPR2/TAG1 colocalization. In cultured neurons, patients’ IgG led to an increase of intracellular CASPR2 without affecting TAG1, suggesting selective CASPR2 internalization. Additionally, mice infused with patients’ IgG showed decreased levels of Kv1.1 and GluA1 (two CASPR2 regulated proteins). All these alterations and the memory deficit reverted to normal after removing patients’ IgG.
Interpretation
IgG from patients with anti-CASPR2 encephalitis cause reversible memory impairment, inhibit the interaction of CASPR2/TAG1, and decrease the levels of CASPR2 and related proteins (VGKC, AMPAR). These findings fulfill the postulates of antibody-mediated disease and provide a biological basis for antibody-removing treatment approaches.Mixed AgBiS2 nanocrystals for photovoltaics and photodetectors
http://hdl.handle.net/2117/363570
Mixed AgBiS2 nanocrystals for photovoltaics and photodetectors
Burgués-Ceballos, Ignasi; Wang, Yongjie; Konstantatos, Gerasimos
Heavy-metal-free colloidal nanocrystals are gaining due attention as low-cost, semiconducting materials for solution-processed optoelectronic applications. One common limitation of such materials is their limited carrier transport and trap-assisted recombination, which impede the performance of thick photoactive layers. Here we mix small-size and large-size AgBiS2 nanocrystals to judiciously favour the band alignment in photovoltaic and photodetector devices. The absorbing layer of these devices is fabricated in a gradient fashion in order to maximise charge transfer and transport. We implement this strategy to fabricate mixed AgBiS2 thin film solar cells with a power conversion of 7.3%, which significantly surpasses the performance of previously reported devices based on single-batch AgBiS2 nanocrystals. Additionally, this approach allows us to fabricate devices using thicker photoactive layers that show lower dark currents and external quantum efficiencies exceeding 40% over a broad bandwidth – covering the visible and near infrared range beyond 1 μm, thus unleashing the potential of colloidal AgBiS2 nanocrystals in photodetector applications.
2022-03-08T13:49:37ZBurgués-Ceballos, IgnasiWang, YongjieKonstantatos, GerasimosHeavy-metal-free colloidal nanocrystals are gaining due attention as low-cost, semiconducting materials for solution-processed optoelectronic applications. One common limitation of such materials is their limited carrier transport and trap-assisted recombination, which impede the performance of thick photoactive layers. Here we mix small-size and large-size AgBiS2 nanocrystals to judiciously favour the band alignment in photovoltaic and photodetector devices. The absorbing layer of these devices is fabricated in a gradient fashion in order to maximise charge transfer and transport. We implement this strategy to fabricate mixed AgBiS2 thin film solar cells with a power conversion of 7.3%, which significantly surpasses the performance of previously reported devices based on single-batch AgBiS2 nanocrystals. Additionally, this approach allows us to fabricate devices using thicker photoactive layers that show lower dark currents and external quantum efficiencies exceeding 40% over a broad bandwidth – covering the visible and near infrared range beyond 1 μm, thus unleashing the potential of colloidal AgBiS2 nanocrystals in photodetector applications.A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation
http://hdl.handle.net/2117/363424
A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation
Woźniak, Aleksander; Lesiuk, Michal; Przybytek, Michal; Efimov, Dmitry K.; Prauzner-Bechcicki, Jakub S.; Mandrysz, Michal; Ciappina, Marcelo; Pisanty, Emilio; Zakrzewski, Jakub; Lewenstein, Maciej; Moszyński, Robert
A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
ACKNOWLEDGMENTS
2022-03-04T10:12:19ZWoźniak, AleksanderLesiuk, MichalPrzybytek, MichalEfimov, Dmitry K.Prauzner-Bechcicki, Jakub S.Mandrysz, MichalCiappina, MarceloPisanty, EmilioZakrzewski, JakubLewenstein, MaciejMoszyński, RobertA precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
ACKNOWLEDGMENTSGeneration of optical Schrödinger cat states in intense laser-matter interactions
http://hdl.handle.net/2117/363421
Generation of optical Schrödinger cat states in intense laser-matter interactions
Lewenstein, Maciej; Ciappina, M. F.; Pisanty, E.; Rivera-Dean, J.; Stammer, P.; Lamprou, Th.; Tzallas, P.
The physics of intense laser–matter interactions1,2 is described by treating the light pulses classically, anticipating no need to access optical measurements beyond the classical limit. However, the quantum nature of the electromagnetic fields is always present3. Here we demonstrate that intense laser–atom interactions may lead to the generation of highly non-classical light states. This was achieved by using the process of high-harmonic generation in atoms4,5, in which the photons of a driving laser pulse of infrared frequency are upconverted into photons of higher frequencies in the extreme ultraviolet spectral range. The quantum state of the fundamental mode after the interaction, when conditioned on the high-harmonic generation, is a so-called Schrödinger cat state, which corresponds to a superposition of two distinct coherent states: the initial state of the laser and the coherent state reduced in amplitude that results from the interaction with atoms. The results open the path for investigations towards the control of the non-classical states, exploiting conditioning approaches on physical processes relevant to high-harmonic generation.
2022-03-04T09:52:31ZLewenstein, MaciejCiappina, M. F.Pisanty, E.Rivera-Dean, J.Stammer, P.Lamprou, Th.Tzallas, P.The physics of intense laser–matter interactions1,2 is described by treating the light pulses classically, anticipating no need to access optical measurements beyond the classical limit. However, the quantum nature of the electromagnetic fields is always present3. Here we demonstrate that intense laser–atom interactions may lead to the generation of highly non-classical light states. This was achieved by using the process of high-harmonic generation in atoms4,5, in which the photons of a driving laser pulse of infrared frequency are upconverted into photons of higher frequencies in the extreme ultraviolet spectral range. The quantum state of the fundamental mode after the interaction, when conditioned on the high-harmonic generation, is a so-called Schrödinger cat state, which corresponds to a superposition of two distinct coherent states: the initial state of the laser and the coherent state reduced in amplitude that results from the interaction with atoms. The results open the path for investigations towards the control of the non-classical states, exploiting conditioning approaches on physical processes relevant to high-harmonic generation.Highly efficient, ultrathin, Cd-free kesterite solar cells in superstrate configuration enabled by band level tuning via Ag incorporation
http://hdl.handle.net/2117/362355
Highly efficient, ultrathin, Cd-free kesterite solar cells in superstrate configuration enabled by band level tuning via Ag incorporation
Wang, Zhuoran; Wang, Yongjie; Konstantatos, Gerasimos
Kesterite, or Cu2ZnSn(S,Se)4 (CZTS) is promising in developing sustainable PV technology due to its earth-abundant, non-toxic composition. However, issues including instability of interface, high density of defects that fails to allow the short charge-collection length to meet its light absorption needs, use of Cd that fails to comply with the restriction of hazardous substances (RoSH), are promoting the development of alternative, eco-friendly device structure. Here, this study reports an important progress on this subject by adopting the superstrate configuration to kesterite, thus to realize advantageous light management and high defect tolerance in an ultrathin device. By incorporating Ag in kesterite to overcome the detrimental alignment at the pristine interface, a solar cell with PCE of 8.1% has been fabricated with ~ 200 nm absorber and ~ 15 nm TiO2 buffer, representing a PCE improvement of nearly three-fold from the baseline Cu2ZnSn(S,Se)4 device and breaking the 5% PCE limit for superstrate kesterite cells to date. Moreover, this enables the sole use of TiO2 as novel buffer material free of toxic Cd. Further analysis reveals the critical role of Ag in synergistically tailoring band offset and bandgap, along with largely reduced density of defects, leading to this substantial performance improvement.
2022-02-14T15:26:07ZWang, ZhuoranWang, YongjieKonstantatos, GerasimosKesterite, or Cu2ZnSn(S,Se)4 (CZTS) is promising in developing sustainable PV technology due to its earth-abundant, non-toxic composition. However, issues including instability of interface, high density of defects that fails to allow the short charge-collection length to meet its light absorption needs, use of Cd that fails to comply with the restriction of hazardous substances (RoSH), are promoting the development of alternative, eco-friendly device structure. Here, this study reports an important progress on this subject by adopting the superstrate configuration to kesterite, thus to realize advantageous light management and high defect tolerance in an ultrathin device. By incorporating Ag in kesterite to overcome the detrimental alignment at the pristine interface, a solar cell with PCE of 8.1% has been fabricated with ~ 200 nm absorber and ~ 15 nm TiO2 buffer, representing a PCE improvement of nearly three-fold from the baseline Cu2ZnSn(S,Se)4 device and breaking the 5% PCE limit for superstrate kesterite cells to date. Moreover, this enables the sole use of TiO2 as novel buffer material free of toxic Cd. Further analysis reveals the critical role of Ag in synergistically tailoring band offset and bandgap, along with largely reduced density of defects, leading to this substantial performance improvement.Widefield SERS for High-Throughput Nanoparticle Screening
http://hdl.handle.net/2117/361685
Widefield SERS for High-Throughput Nanoparticle Screening
Liebel, Matz; Calderon, Irene; Pazos-Perez, Nicolas; van Hulst, Niek F.; Alvarez-Puebla, Ramon A
Surface-enhanced Raman scattering (SERS) imaging is a powerful technology with unprecedent potential for ultrasensitive chemical analysis. Point-by-point scanning and often excessively long spectral acquisition-times hamper the broad exploitation of the full analytical potential of SERS. Here, we introduce large scale SERS particle screening (LSSPS), a multiplexed widefield screening approach to particle-characterization, which is 500-1000 times faster than typical confocal Raman implementations. Beyond its higher throughput, LSSPS simultaneously quantifies both the sample’s Raman and Rayleigh scattering, allowing for an unprecedented correlation of SERS activity with the particle-size and to directly quantify the fraction of SERS active particles.
2022-02-04T10:36:10ZLiebel, MatzCalderon, IrenePazos-Perez, Nicolasvan Hulst, Niek F.Alvarez-Puebla, Ramon ASurface-enhanced Raman scattering (SERS) imaging is a powerful technology with unprecedent potential for ultrasensitive chemical analysis. Point-by-point scanning and often excessively long spectral acquisition-times hamper the broad exploitation of the full analytical potential of SERS. Here, we introduce large scale SERS particle screening (LSSPS), a multiplexed widefield screening approach to particle-characterization, which is 500-1000 times faster than typical confocal Raman implementations. Beyond its higher throughput, LSSPS simultaneously quantifies both the sample’s Raman and Rayleigh scattering, allowing for an unprecedented correlation of SERS activity with the particle-size and to directly quantify the fraction of SERS active particles.